Secondary treatment is the second stage of wastewater treatment. Oil, grease, and colloidal particles are eliminated during basic or primary treatment.
To eliminate the organic substances present, biological treatment is applied to the wastewater during secondary treatment. Local and aquatic bacteria and protozoa that devour biodegradable soluble pollutants, like sugar, fat, detergent, and food waste carry out this treatment.
These processes are temperature-sensitive, and when the temperature rises, biological responses proceed more quickly.
Processes involved in the secondary treatment of wastewater
Two distinct treatment procedures make up secondary wastewater treatment:
1. Aerobic Treatment: This biological process for treating wastewater breaks down organic debris and removes other contaminants, like nitrogen and phosphorus by using oxygen.
Technologies for aerobic treatment include:
· Extended Aeration System (EAS)
· Activated Sludge Process (ASP)
· Sequential Batch Reactor (SBR)
· Moving Bed Biofilm Reactor (MBBR)
· Membrane Bioreactor (MBR)
2. Anaerobic Treatment: In anaerobic treatment, microorganisms break down waste or other materials without the use of dissolved oxygen. However, anaerobic bacteria can and will utilize the oxygen present in the system's supplied oxides, as well as the organic matter in the effluent.
Technologies for anaerobic treatment system include:
· Up-flow sludge blanket reactor for anaerobic sludge (UASB)
What are the Wastewater treatment products for secondary treatment?
1: Extended Aeration System and Activated Sludge Process
· The Extended Aeration process's mixing regime and organisational structure, are comparable to those of the fully mixed process.
· Low organic loading, prolonged aeration, high MLSS concentration, and low F/M are all used in the process.
· There is high elimination effectiveness for BOD.
· The mixed liquor solids experience significant endogenous respiration, and becomes well stabilized as a result of their prolonged detention in the aeration tank.
· The system's overall running costs are impacted by the increasing oxygen need.
· However, the removal of initial settling and separate sludge digestion, simplifies the process.
2: Sequential-Batch-Reactor (SBR)
· For the treatment of sewage, a sequential batch reactor uses an active sludge system.
· In a single batch reactor, equalisation, aeration, and clarification can all be accomplished. For big industrial effluents, the SBR system is effective.
· The SBR does away with the requirement for an additional clarifier.
· Since, the process is PLC-based, SBR requires more maintenance while in operation, but it also exhibits higher efficiency and requires less space for the ETP.
· Settlement and secondary treatment are combined in SBR. With a mixture of wastewater and activated sludge, oxygen is bubbled in order to remove the organic matter (BOD and COD).
· The water can then be dumped onto surface waters after this treatment.
· An aeration tank, similar to an activated sludge tank and unique plastic carriers give a moving bed biofilm reactor (MBBR) a higher surface area, where a biofilm can form.
· The Membrane Bioreactor (MBR) combines the activated sludge and ultrafiltration processes.
· High-quality effluent from MBR can be released into surface water for reusing.
· It is adaptable to existing installations.
5: Up-flow Anaerobic Sludge Blanket Reactor (UASB)
· Up-flow anaerobic sludge blanket (UASB) reactor is an anaerobic digester.
· A methane-producing digester known as the UASB reactor uses an anaerobic process, to create a layer of granular sludge, which is then broken down by anaerobic microorganisms.
· UASB assists in reducing greater organic loads so that the remaining loads can be treated aerobically, in the case of higher organic loads.
· The substrate typically goes through an enlarged sludge bed, with a high concentration of biomass, during the treatment of the UASB reactor.
· The remaining portion of the substrate next travels through a layer of less dense biomass, known as the sludge blanket.
· Through a sludge recirculation cum disposal pump, the sludge is mixed and circulated. The extra granular sludge is dumped into beds for drying the sludge.
The presence of anoxic conditions is necessary for denitrification to take place. Although, dissolved molecular oxygen is scarce under anoxic circumstances, it is possible for oxygen to be chemically bonded, as is the case with nitrate.
Both an electron donor and an electron acceptor are needed for the dissimilation process, to break down the nitrate molecule into chemically bonded oxygen. A carbon source loses (donates) electrons and is oxidized to carbon dioxide, while nitrate obtains (accepts) electrons and is reduced to nitrogen gas.
Simply put, anoxic circumstances make sure that nitrate, rather than oxygen, will act as an "electron acceptor" in the dissimilation process. Nitrate-rich mixed liquor injected from the effluent end of the aeration tanks, is combined with return sludge from the clarifier, in the pre-anoxic basin influent wastewater.
How can we assist?
The infrastructure and unique technologies required for efficient water treatment, including recycling and recovery are available from Netsol Water. Major companies all over the world use our water conservation solutions for industrial, commercial, and municipal applications.
Given the increasing requirement to conserve and recover water, water efficiency is an essential part of every modern establishment. We have the technologies, expertise, and experience, necessary to offer specialized wastewater treatment solutions.
Choosing the best manufacturers of wastewater treatment plants in India
Netsol Water is one of the top producers of wastewater treatment systems in India.At Netsol, we are committed to providing high-performingwastewater products for secondary treatment, to assist enterprises with their wastewater, and sewage requirements.
We have earned a reputation for providing top-notch service and solutions, which will help our clients lower operating expenses and increase the life of their equipment. Every purchase of these systems includes free installation, manufacturer's warranty, and a 24-hour customer service, after the sale.